The present disclosure relates to a solid-state imaging device, a light detecting device, and an electronic apparatus, in particular, to a solid-state imaging device, a light detecting device, and an electronic apparatus for the detection of infrared light and for which it is possible to improve mass production and lower costs.
In recent years, there has been a demand for inexpensive detecting devices or image sensors having a sensitivity to infrared (IR) light from near infrared to mid-infrared with a wavelength of 1 μm or more. As a range of applications, there are surveillance cameras or vehicle cameras which are able to be used at night, detectors for preventing collisions which are also vehicle-mounted, medical or agricultural applications such as being able to detect amounts of moisture, and the like.
In an IR light image sensor, for example, there is a sensor with a photoelectric conversion section where an InGaAsSb based material is set to a Multi-Quantum Wells (MQW) structure on an InP substrate. Japanese Unexamined Patent Application Publication No. 2011-222874 describes imparting sensitivity to IR light of a longer wavelength by forming a superlattice (MQW) structure (Type II) of an InGaAs layer and a GaAsSb layer on an InP substrate and causing this to function as a photoelectric conversion section.
However, in the case of an InP substrate, the size of the InP substrate is as small as 2 to 3 inches and is not suited to mass production. In addition, in terms of cost, one substrate is expensive at tens of thousands of yen.
On the other hand, there are also sensors where an SiGe based material on an Si substrate which is able to increase the area at a low cost is set as a photoelectric conversion section.